Adaptive Speed Sensorless Vector Control of Induction Motor using Singularly Perturbed Sliding Mode Observer

This paper presents a new approach for sensorless vector control of induction motor using singularly perturbed sliding mode observer. This approach is based on the singular perturbation theory which decomposes the original system of the observer error dynamics into separate slow and fast subsystems and permits a simple design and sequential determination of the observer gains. In this way, the flux observer accuracy (slow dynamics) is guaranteed through the current observer (fast dynamics). The rotor speed and the rotor resistance are estimated by adaptive laws based on measured and estimated stator currents and estimated rotor flux. The effectiveness of this new approach has been successfully verified through computer simulations, where the control algorithm is based on the indirect field oriented sliding mode control